New science played key role in decision banning juvenile executions

WASHINGTON—The briefs read like doctoral theses on adolescent development, with charts and graphs and references to longitudinal studies. They're as much about science as they are about the law—and in the Supreme Court's decision to outlaw executions for child killers, they played a pivotal role.

As much as Justice Anthony Kennedy relied on constitutional analysis to reach the court's ruling in Tuesday's landmark decision, he also banked on volumes of research—much of it recent—that was submitted to the court by the scientific community to persuade the justices that youthful minds are fundamentally different.

"We've seen extraordinary strides in research and in the technological capacity to conduct that research, and that has fundamentally changed the way we view youth," said Marsha Levick, the legal director at the Juvenile Law Center, a national advocacy group for juvenile offenders. "There's real science to draw on now, and I think it's an important moment in legal and constitutional history that the court now recognizes that."

As more is learned about the brain, Levick said, its development is better understood. When the court last considered juvenile executions in 1989 and left 16- and 17-year-olds eligible, much of that knowledge wasn't available.

But now, new research—some involving magnetic resonance imaging of the brain—has shown that critical parts of the mind develop later than previously believed, robbing even late-year teenagers of the impulse control and decision-making ability of people just a few years older.

"Emerging from the neuropsychological research is a striking view of the brain and its gradual maturation, in far greater detail than seen before," the American Psychiatric Association said in its brief to the court. "Although the precise underlying mechanisms continue to be explored, what is certain is that, in late adolescence, important aspects of brain maturation remain incomplete, particularly those involving the brain's executive functions."

Kennedy said the evidence in the studies led to the conclusion that the punitive justifications for the death penalty apply to youth with lesser force than adults. It also obliterates the justification for the death penalty's retributive motivations.

"Retribution is not proportional if the law's most severe penalty is imposed on one whose culpability or blameworthiness is diminished ... by reason of youth and immaturity," Kennedy wrote.

Levick pointed out that the high court is far from the first to use research to justify treating adolescents differently.

"Most states won't let them get tattoos, or get married, or even go to a tanning salon without parental consent," Levick said. "It's indisputable that nationwide we now think of youth as distinct."

Not everyone buys into Levick's assertions or Kennedy's use of the research to help guide constitutional analysis.

Justice Antonin Scalia, who penned the fiercest dissent to the court's ruling, accused the court majority of "picking and choosing" the research that supports its position.

"We need not look far to find studies contradicting the court's conclusions," Scalia wrote. In particular, Scalia singled out the American Psychiatric Association, whose position on youthful immaturity was cited by Kennedy.

The group took "precisely the opposite position before this very court" in a 1990 case about whether minors could choose to have abortions without parental consent. The group said that by age 14 or 15, teenagers are similar to adults in their "reasoning about moral dilemmas, understanding social rules and laws, and reasoning about interpersonal relationships," Scalia noted.